This invention concerns in general open-end friction spinning, and in particular a method and apparatus for open-end friction spinning in which fibers are twisted together into a yarn in a spinning nip formed by two friction rollers located in close proximity of each other and driven in the same direction. The yarn is drawn off from the spinning nip generally in the direction of the rotational axes of the friction rollers.
In open-end friction spinning, fiber material is conventionally separated (i.e. opened) into individual fibers which are then brought into a spinning nip formed by two rotating friction rollers. The rollers are typically in close proximity of each other and driven in the same rotational direction. The individual fibers in the spinning nip are twisted together into a yarn by the rotation of the friction rollers. The yarn is drawn off in the direction of the spinning nip by means of a pair of draw-off rollers.
Known methods of feeding fibers for open-end friction spinning generally include feeding separated fibers directly into a spinning nip (e.g. German Pat. DE-PS No. 2,449,583, corresponding to U.S. Pat. No. 3,913,310), or feeding them at a distance from the spinning nip (on the yarn-forming side) to a friction roller which is embodied as a suction roller and which rotates into the spinning nip. The fibers are then conveyed into the spinning nip on the casing surface of the suction roller. This latter method is exemplified by German Pat. DE-OS No. 3,300,636. The quality of yarn thus produced is often considered unsatisfactory, because the individual fibers are not sufficiently stretched and oriented when they are incorporated into the body of fibers forming the yarn.